Frailty score may help predict postop mortality risk in the elderly

A multidimensional frailty score helped predict postoperative mortality risk in elderly patients, according to a new study.

Researchers at a tertiary care center in Korea studied consecutive patients at least 65 years of age who were having intermediate-risk or high-risk elective surgery. Patients who had emergency surgery or who were classified as low risk for adverse outcomes after surgery according to American College of Cardiology/American Heart Association 2007 guidelines were excluded. The goal of the study was to develop a model that would predict adverse outcomes in elderly patients undergoing surgery. To that end, all patients received a comprehensive geriatric assessment, which involved burden of comorbidity, polypharmacy, physical function, psychological status, nutrition, and risk for postoperative delirium. Most received the assessment within a month prior to surgery, although 13 received it 1 to 3 months before surgery.

The study's main outcome measure was all-cause mortality at 1 year, while secondary outcomes were postoperative complications (unplanned ICU admissions, pneumonia, delirium, urinary tract infection, or acute pulmonary thromboembolism), length of stay, and discharge to a nursing facility if the patient had previously lived at home. The study results were published online May 7 by JAMA Surgery.

From Oct. 19, 2011, to July 31, 2012, 275 patients were included in the study. Mean age was 75.4 years, and 55% were men. Twenty-five patients (9.1%) died during a median follow-up of 13.3 months, 4 in the hospital after their surgery. At least 1 postsurgery complication occurred in 29 patients (10.5%), and 24 patients (8.7%) were discharged to nursing facilities. Patients who died were more likely to have malignant disease and low levels of serum albumin than those who did not. Higher mortality rates were associated with scores on the Charlson Comorbidity Index (a method of predicting mortality by weighting comorbid conditions), dependence in activities of daily living and instrumental activities of daily living, dementia, delirium risk, short midarm circumference, and malnutrition.

The researchers developed a frailty score based on these factors and found that it performed better when predicting rates of all-cause mortality than the American Society of Anesthesiologists score (area under the receiver-operating characteristic curve, 0.821 vs. 0.647; P=0.01). Based on the frailty score, patients were divided into those with a score greater than 5 and those with a score of 5 or lower, with a higher score indicating higher risk. Sensitivity was 84.0% and specificity was 69.2% for all-cause mortality. Patients with high-risk frailty scores had higher risk for death (hazard ratio, 9.01; P=0.003) and longer hospital stays (median, 9 vs. 6 days; P<0.001) after surgery.

The researchers noted that their study involved a single hospital and that the results therefore might not be generalizable to other settings. In addition, they pointed out that their model did not show statistical significance when predicting outcomes after surgery. However, they concluded that their score, which is based on a comprehensive geriatric assessment, is better than other conventional methods when predicting 1-year all-cause mortality rate after surgery, length of hospital stay, and risk for discharge to a nursing facility.

“This model may support surgical treatments for fit older patients at low risk of complications, and it may also provide an impetus for better management of geriatric patients with a high risk of adverse outcomes after surgery,” the researchers concluded.